Switch



Jan. 21, 1930. J, EURKHQLDER 1,744,029

SWITCH Filed Feb. 6, 1928 2 Sheets-Sheet l HIM l I 2 2w 9 av A TTORNE Y.

Jan. 21, 1930. J. D. BURKHOLDER SWITCH.

Filed Feb 6, 1928 V 2 Sheets-Sheet 2 Mm QQR A TTORNEY.

Patented Jan. 21, 1930 JOHN D. BURKHOLDER, or HARRISONBURG, vxneim'swrrcn Application filed February 6, 1923. Serial No. 252,312.

This invention relates to a switch for controllingthe energization of atherapeutic appliance, in the useof which provision is made for theautomatic; intermittent control of the energization; for the control ofthe energization by the room temperature; and

for the control of the energization for certain defined time periods.

In the use of a therapeutic appliance, such for example as a blanket orpad or both, constructed to aflord certain remedial efiects through theenergization of such elements byit may be desirable to set theenergization for a predetermined period or periods, in order thatthrough these: various controls the requirements of any particulartreatment may be readily provided for.

The improved switch of the present construction is particularly designedto provide in a single unit themeans for governing the variousenergizations of the therapeutic appliance merely through the manualsetting of the switch in'a selective manner and in a single operation;the switch of course also contemplating the manual control of theenergization at will.

The invention also provides for the periodic energization anddeenergization of the therapeutic appliance through an appropriate clockcontrol which operates through the switch.

The invention is illustrated in the accompanying drawings, in which:.

Figure l'is a view in elevation showing the switch in external form asarranged in the cord connected to the therapeutic appliance and adaptedfor the usual plug connection with the service outlet.

Figure 2 is a top plan view ofthe switch proper, the casing of coursebeing omitted.

Figure 3 is a bottom plan view of the same.

Figure 4 is a section on line H of Figure 2.

Figure 5 is a section 'on line 5 5 of Figure 2. i

Figure 6 is a section through the switch casin showing the manualcontrol elements for the switch. I

Figure 7 is a transverse section through one of the therapeuticelements.

Figure 8 is a diagrammatic view of the switch and circuits.

The switch proper comprises an insulating base 1, overlying the uppersurface-of which are arranged three independent spring strips 2, 3 and4. These strips, which will be hereinafter termed contact strips, aresecured at their ends at 5 at one end of the base, rising from suchfixed point and overlyingand extending longitudinally of the base, thefreeend 6 of each strip being adapted, when the strip has been depressedinto contact position, to engagethe hook term1nal'7 of a latch 8pivotally supported at .9 on one end of the base and having atailportion 10 through which the latch may be operated to release thestrip in a manner to be later described.

It is to be understoodthat the contact strips are of such inherentresiliency that when free of the latches, the ends 6 of the strips arearranged some distance above the base, and that when manually operatedas will pres ently appear, the free ends of the strips or the selectedstrip is depressed into contact position and held in such position bycooperatiom-with the latch, as clearly shown in Figure 4:. I

Underlying the contact strips and secured upon the upper surface of thebase is an L-shaped contact plate 11, one arm 12 of which extendstransversely of the base, underlying the strips. The contact strips andtransverse arm 12 of the plate 11 are provided with contact pointsindicated for-the respective strips at 13, 14 and 15, so that when theparticular strip is depressed and within 100 the holding influence ofits latch, such strip will be in electrical contact with the plate 11.Secured on the lower surface of the base 1 and extending longitudinallyof thebase adjacent one side edge thereof is aplate 16, hereinaftertermed the control contact, an auxiliary control contact in the form ofa plate 17 of materially less length than the plate 16 being arranged inlongitudinal alignment with but in spaced relation to the plate 16.

A heating coil 18 is arranged longitudin'ally of the bottom surface ofthe base at the edge opposite the control contacts, and contact bars 19,20 and 21 are arranged for control by the heating element and forcooperation with the control contact, a similar contact bar 22 beingarranged for control by the heating coil and for cooperation with theauxiliary contact 17. The contact bars are terminally secured to thebase beneath the heating coil 18 and are curved partially around andspaced from the coil and extended across the same to and above thecontact controls. r

The bars 19, 20,21 and 22 are of bi-metallic formation in order tomovably respond to different heat conditions, the respective metals ofthe bars being of diflerent coeficients of contraction and expansion aswell understood. Thus, the contact bars, as will later more specificallyappear, will occupy one position relative to the contact controls whenthe bars are in non-heated condition and the opposite position relativeto such controls when the bars are in heated'condition resultant fromthe energization of the heating coil 18.

The bars 19, 20 and 21, which 'engagewith the contact control 16, areprovided at their free ends with contact points 23, 24 and 25, while thecontact bar 22, which cooperates with the auxiliary contact control 17,is providcd at its free end with a contact point 26. These respectivecontact points cooperate, as is well understood, with the contact pointson the respective controls, so that, when the particular contact bar isin operative position, the bar and control are in electrical engagement.

As the contact strips 2, 3 and t constitute the control elements for thecircuitsand as these circuits under certain conditions are to beautomatically broken, means are providedfor releasing the strips 2, 3and 4: from contact position, that is to say,-for tripping the" latches8 to permit the contact strips through their inherent resiliency to moveto open circuiting positions. This release means includes thermostaticbars 27 and 28 secured at one end on the under side of the base andextending across and below the contact bars 19, 20, 21 and 22 and formedat their free ends with cross strips 29 adapted to cooperate with thetail portions 10'of adjacent pairs of latches. There are twothermostatic bars and the operation of either will actuate two latches,the intermediate or central latch being operated by either thermostaticbar. The thermostatic'bars are ofthe usual bi-metallic character heatedby a coil 30, the circuiting of which will later appear.

In connection with the automatic intermittent control of the.energization of the therapeutic appliance, it is of course necessarythat the circuit or certain *of the circuits be automatically closedfollowing their automatic interruption in order to provide theintermittent automatic operation. For this purpose, certain of thecontact strips, for example contact strips 3 and 4, are provided withautomaticv operating or setting means. Such setting means includesthermostatic bars 31 and 32 arranged above the respective strips 4 and5, such thermostatic bars being of the usual bi-metallic characterheated by encircling coils 33. The free ends of the bars overliethecontactstrips 3 and 4 near their free ends and the respective metals ofthe bimetallic thermostatic bar are so arranged that when the bar isheated, the free end will move downwardly and thereby move the free endof the particular contact strip into cooperation with its latch or intocircuiting position.

The therapeutic appliance is here illustrated as a blanket Set and a pador pads 35,

and the circuits for the various switch parts in their control of theenergization of this therapeutic appliance are diagrammaticallyillustrated in Figure 8. In this connection, as will be plain fromFigure 8, it will be understood that in the normal-condition of theswitch, the contact bar 22 is normally in electrical engagement with theauxiliary contact 17; the contact bar 21 is normally free or spaced fromthe cooperating contact of the contact control plate 16; while thecontact bars 20 and 19 are normally free of electrical engagement withthe contact control- 16. The respective bars 19, 20, 21 and 22 are, asstated, thermostatic bars in their bimetallic formation and are to beoperated under heat conditions. That is to say, bar

22 is normally closed at room temperature and opens under apredetermined degree of heat; contact bar 21 is normally open and isdesigned to close when the room temperature falls to a predetermineddegree; contact bars 20 and 19 are time control bars and are so formedas to respond to a predetermined degree of heat at difi'erent periods oftime, for example, bar 20 closes under a predetermined degree of heat inten minutes while bar 19 closes under a predetermined degree of heat infifteen minutes.

The incoming conductor 36, which as stated forms part of the cordleading from the usual plug to be inserted in the box of the mainservice terminals, leads directly to the contact control 16, so thatthis contact control plate is a live plate when the current ductor 37branching from the conductor 36 and leading directly to the heatingcoil. This conductor 37, which is in the form of a resistance conductor,is of sufiicient length to take care of the current and by arranging thesame in the cord, provision is made for taking care ofthe currentdemands without utilizing any portion of the switch or blanket wiringfor the purpose.

The contact strips 2, 3 and 4 are, as stated, when in circuitingposition, in electrical contact with the plate 11 and thisplate isterminally connected through conductor 38 with the outgoing conductor 39of the cord. The fixed end of contact strip 2 is connected throughconductor 40 with the therapeutic appliance direct, leading through thepad '35 and blanket 34 in series, the conductor 40, which leads throughthe blanket, being connected at its opposite end to the heating coil 18.The

contact strip 3 is connected by conductor 41 tothe contact bar 22, theauxiliary contact control 17 being connected by conductor 42 with theblanket energizing conductor 40 beyond the pad, thus shunting the padwhen the energizing circuit is through the bar 22 and auxiliary contactcontrol 17. i

The contact strip 4 is connected through 'conductor 43 with conductor 40beyond the contact strip 2, serving on depression of the contact strip 4to energize both the pad and blanket The release thermostat 27, whichcontrols the release of contact strips 2 and 3, has its coil 30 incircuit with the contact strip 2 through conductor 44 at one end andthrough conductor 45 leading to contact bar 20 at the opposite end. Thethermostatic release 28, which serves contgt strips 3 and 4, has itscoil 30 connected at one end by conductor 46 to the contact strip 4, theopposite end of the coil being connected by conductor 47 to the contactbar 19. V

The settingthermostat 31, which is adapted I to set or move intocircuiting position the contact strip 3, has its coil 33 connected atone end byconductor 48 withthe plate 11 and at the opposite end throughconductor 49 with the contact bar 21. The thermostatic setting bar 32,which is adapted to set the contact strip 4 into circuiting position,has its coil 33 connected atf'one end of a conductor 50 with the plate11, its opposite end being connected by a conductor'51 with and form ingpart of a circuit for a clock control. s

In the use of therapeutic appliances of this character, it is frequentlydesirable that the energization be controlled throughtlie medium of aclock designed for the purpose in. which, by the setting of contacts, aperiodic energization will take place every hour. Such a clock isconventionally illustrated at 52, the circuiting features of whichinclude a fixed circuit wire 53 branching from the resistance 37 oftheincoming wire. able contact points of the clock to be engaged by thehand 54 include a conductor 55 which leads to and is in electricalconnection with the conductor 47 of the coil 30 of the thermostaticrelease 28, the remaining variable contact of the clock being part ofthe conductor 51 hereinbefore referred to.

The switch is enclosed in a cylindrical twopart casing 56, in one partof which the base 1 is removably fixed by screws 57. Pushbuttons 58, 59and 60 are mounted in the shell of the casing overlying the contactstrips 2, 3 and 4 respectively to permit manual op- The vari- 1 leasepush-button 61 is mounted in the casing. and provided with a head 62which overlies both of the release thermostats 27 and 28, so that ondepression of this button 61, any or all of the latches set may bemanually released.

In operation, if it is desired to provide an automatic intermittentenergization of a therapeutic element, the contact strip 3 is moved inclosed position by operation of the push-button 59. The current nowflows through the lead-in wire 36, blanket conductor 40, conductor 42,auxiliary contact control 17, contact points 26, contact bar 22,conductor 41, spring strip 3, plate 11, conductor 38, and outgoing wire39. The contact points 26 are normall closed and as the points 26separate. The current is broken at this point and the blanket isdeenergized. As the temperature falls in the room, the contacts 26 againclose and the blanket is again energized. This "intermittentenergization and deenergization is maintained automatically and withoutattention on the part of the operator.

If it is desired that the blanket become deenergized at a particularroom temperature for which the thermostatic bar 21 may beset, it will beapparent that when this room ternperature is reached, contacts 25 willclose and the current then flows through incoming resistor conductor 37,contact control 16, contacts 25, conductor 49, setting thermostat 31,conductor 48, conductor 38, and outgoing conductor 39. The spring strip3 is then moved into circuiting position by the setting thermostat31and-the current is then controlled by the intermitent thermostat contactbar 22 in the manner previously described.

If a constant heat for a predetermined period, say ten minutes, isdesired, push-button 58 is operated to move contact 2 to circuitingcontact bar 22 is heated y the coil 18, the i blanket conducton throughcontact strip 2, plate 11, and conductors 38 and 39. As the coil 18 isheated, the thermostat contact bar 20 responds inthe predetermined time,that is ten minutes, to close the contacts 24. Current is then sent fromthe contact control 16, through contacts 24, arm 20, conductor 45,release thermostat coil 30 and to the outgoing conductor. The thermostat27 then operates to release the latch holding the contact strip 2 andthe latter opens, breaking the blanket circuit.

- If a longer period of energization is desired, push-button 60 isoperated to' set con tact strip 4. The current then flows throughtheblanket as previously described until coil 18 causes contact 23 toengage by operating thermostat contact bar 19. The coil 30 of releasethermostat 28 is then operated and spring strip 4 released from itslatch to break the circuit.

In the clock control, when the hand 5 L contacts with the terminal ofconductor 51,

setting thermostat 32 is operated to close spring strip 4, providing thecircuit previously described for the energization of the blanket. Whenthe hand contacts with the terminal of conductor 55, the releasethermostat 28 is operated to release the latch holding spring strip 4in'circ'uiting relation. The circuit is broken by the release of thisspring strip. Thus the contact terminals of the clock may be adjusted toclose and open the circuit at selected intervals.

What I claim to be new is:

1. In a switch for controlling the energization of a therapeuticappliance, current controlling strips, means for manually operating thestrips to circuiting positions, means for automatically releasing thestrips from circuiting positions under predetermined heat conditions,and means for automatically moving certain of the strips to circuitingpositions undercertain predetermined heat conditions. i

2. In a switch for controlling the energiza- 1' tion of a therapeuticappliance, a plurality of contact strips, means for movlng the strips tocircuiting positions, locking-means for holding the strips in circuitingpositions, thermostatic elements for releasing the locking means topermit the strips to move to noncircuiting positions, and otherthermostats cuiting positions, a heating coil carried by the switch, andthermostat controlling contacts operated by the heating coil.

' 4. In a switch for controlling the energi- Zation of a therapeuticappliance, a plurality of contact strips, means for moving the strips tocircuiting positions, locking means it'or holding the strips incircuiting positions,

tacts operated by the heating. coil, said contacts bein'g'arranged torespond to varying heat periods.

5. In aswitch for controlling the energization of a therapeuticappliance, manually operable spring strips for controlling circuitsleading to the therapeutic appliance, means.

for locking the spring strips in circuiting positions, a thermostat forreleasing the locking means under predetermined heat conditions,thermostats for automatically operating the spring strips to circuitingpositions means, thermostatic contacts for controlling the locking meansreleasing thermostats and 'the spring strip operating thermostats, and

a heating element for controlling the thermostatic contacts.

6. In a switch for controlling the energiza tion of a therapeuticappliance, manually.

operable spring strips for controlling circuits leading to thetherapeutic appliance, means for locking the spring strips in circuitingpositions, a thermostat for releasing the locking means underpredetermined heat conditions, thermostats for automatically operat JOHND. BURKHOLDER.

operative to compel movement of the strips to circuiting positions.

3. In a switch for controlling the energization of a therapeuticappliance, a plurality'of contact strips, means for moving the strips tocircuiting positions, locking means for holding the strips in circuitingpositions, thermostatic elements for releasing the' locking means topermit the strips to move to noncircuiting positions, other thermostatsoperative to compel movement of the strips to cirand within theinfluence of the locking

